The imprint technique is attracting a great deal of attention as one of nano-lithography techniques for volume production of, for example, magnetic storage media and semiconductor devices. In the imprint technique, a pattern is transferred onto a substrate such as a silicon wafer or a glass plate using, as an original, a mold having a fine pattern formed on it.
An imprint apparatus which uses the imprint technique often adopts the die-by-die alignment method as an alignment method between a substrate and a mold. The die-by-die alignment method is an alignment method in which an alignment mark formed in each of a plurality of shot regions on the substrate is optically detected, and a deviation in positional relationship between the substrate and the mold is corrected. In such a method, a method of alignment using not only an alignment mark on a mold, which corresponds to an alignment mark on a substrate, but also a mark for obtaining the information of its position relative to the alignment mark has been proposed in Japanese Patent No. 4185941.
A mold used in an imprint apparatus generally has a rectangular pattern region (a region where a pattern is formed), and alignment marks are formed at the four corners of its peripheral portion surrounding the pattern region. An imprint apparatus aligns a substrate and a mold using an alignment mark formed on the peripheral portion surrounding the pattern region. However, when alignment is performed using the alignment mark formed on the peripheral portion surrounding the pattern region, it is often the case that the positional relationship between the substrate and the mold is correct on the peripheral portion but is incorrect in the pattern region. If, for example, nonlinear distortion has occurred in the mold (that is, if the distortions of the pattern region and peripheral portion of the mold are different from each other), a position deviation between the substrate and the mold occurs in the pattern region, resulting in an overlay error. Note that nonlinear distortion easily occurs in the mold upon deforming the mold or filling the pattern region of the mold with a resin.